He has instructed the museum to tack the bills up vertically, not horizontally, and they will have to overlap to get the entire $100,000 on the walls. Why vertically? Mr. Feldmann said it was an entirely pragmatic decision: "it's easier because they only will need one pin."

"Hey, cash this check in $1 bills, then tack them all to the walls. Call me when it's ready," said the great artist. The museum staff eyed each other dubiously. Had this all been a big mistake? "Oh," added the artist, "do it vertically."